The present invention relates to a universal vise that permits indexing the movable jaw to at least several positions and providing a jaw hold down force in each position as the movable jaw is clamped. The vise nut drive system permits both the movable and fixed jaws to be indexed at selected increments, as shown 90.degree. increments, to provide different jaw surfaces for engaging a workpiece in each of the indexed positions.
Problems with chips falling on the vise screw are avoided by supporting the movable and fixed jaws above the plane of the vise guideway surfaces and forming the vise jaw nut to have a rib forming a shield between the guideways. The nut provides the guide keys for the movable jaw allowing the movable jaw position to be guided without projecting below the vise top surface.
In the prior art there are machine vises that include a cover over the vise screw and between the spaced apart guideways that are used for supporting the movable jaw. The cover closes the space above the vise screw to protect the screw from falling chip contamination. The opening overlying the vise screw is shielded or plugged so that chips do not fall onto the vise screw. Such a shield is shown in U.S. Pat. No. 5,442,844.
Because of the universality of machine vises, and the need for holding a plurality of irregularly shaped parts, many vise jaws are now adapted so that they can be "carved" to conform to the surface of the workpiece that they are to hold. The ability to carve the vise jaws is an important feature for universal use.
Prior art jaws which provide a hold down force as the movable jaw is clamped have a recess in the bottom of the movable jaw that receives a head portion of the nut with a load applying hook reacting against a part spherical seat washer. This caused the jaws to have either a very high profile, or in some instances, a relatively thin layer of metal over the recess, which restricts the depth of contouring that can be done for a part on the top of the movable jaw.
Prior vise jaws which provided a hold down force on the movable jaw also were made with a cast in loading surface along one side of the recess of the jaw forming the spherical seat. Thus only one side surface of such movable jaw can be used for holding a workpiece.